As coding and information compression technologies develop and digital networks rocket, videoconferencing systems start to step into the market. When IP (Internet Protocol, Internet Protocol) network technologies move toward maturity, IP networks become an important network platform for global communications. The ITU-T (International Telecommunication Union-Telecommunication Standardization Sector, International Telecommunication Union-Telecommunication Standardization Sector) puts forward the H.323 videoconferencing standard based on IP networks. This swerves the research and application direction of a videoconferencing system to development based on IP networks.
Today, a videoconferencing system based on the H.323 videoconferencing standard is finding increasingly wide use with the rapid development of IP networks. Most of departments, such as the government, the army, and enterprises, have deployed their own videoconferencing system to improve meeting efficiency and save meeting costs.
Telepresence (Telepresence), a new technology, emerges in the videoconferencing market. Remote participants are at another end of a network, but their images are displayed in true-to-life dimensions on a display device in a conference room, and a user does not feel any discomfort or difference. A perfect combination of a video image in true-to-life dimensions, a high-definition image effect, an audio system with a sense of space, and the environment creates a sense of being in the same conference room with the remote participants. A complete set of a telepresence system needs to consist of an appropriate conference room, power, a high-bandwidth network channel, an independent wall, a desk, a chair, a light, a video display device, a control device, and an audio device. Compared with a conventional conferencing system, a telepresence system has its unique advantages, that is, it not only saves travel expenses but also significantly improves conference quality. In addition, telepresence overcomes the plane and unreal effects of a conventional video conference and makes a conference more natural, thereby improving conference efficiency.
In the telepresence technology, each camera at a local conference site corresponds to a different user area, and each camera simultaneously captures an image of a corresponding user area and sends it to a conferencing terminal at a remote conference site; the conferencing terminal at the remote conference site stitches, by using a physical or digital image stitching technology, images captured by cameras at the local conference site, and then outputs them to adjacent display devices at the remote conference site for displaying; and a conferencing terminal at the local conference site may also stitch, by using a physical or digital image stitching technology, images captured by cameras at the remote conference site, and then outputs them to adjacent display devices at the local conference site for displaying. For the purpose of implementing image stitching without a mismatch, a certain fixed model of display devices are generally selected at the local conference site and the remote conference site, or at least frames of the display devices are the same.
In the prior art, image stitching without a mismatch requires that the width of a blind spot between two adjacent images equal the minimum edge gap between displayable areas of two adjacent display devices. The minimum edge gap may also be called the width of a gap between display devices. If the displayable areas of the display devices occupy the entire screens of the display devices, the width of a gap between the display devices basically equals the sum of the width of frames of the two adjacent display devices. Such stitching without a mismatch will not make a user feel that an image is mismatched, thereby better satisfying a reality requirement of the telepresence technology. Here, the blind spot is a conference scenario area that is not covered by the adjacent images. If the adjacent images are images shot by adjacent cameras, the blind spot is specifically a conference scenario area that is beyond shooting areas of the adjacent cameras. A displayable area is the largest display area that hardware of a display device can support, and the area is generally rectangular.
For the purpose of implementing image stitching without a mismatch, it is required that the width of a blind spot between adjacent images equal the width of a gap between adjacent display devices that are used to display the adjacent images at a target end. However, as display devices are continually replaced by new ones, screen dimensions and frame sizes of the display devices change accordingly. If the width of a gap between display devices at a target end is inconsistent with the width of a blind spot between the adjacent images, this may lead to a mismatch in image stitching at the target end, thereby affecting user experience.